Comanche Peak in Glen Rose, Texas, is one of the newer U.S. nuclear power plants. Although construction on the plants began years earlier, its two units became commercially operational in 1990 and 1993, respectively. A new bill pending in Congress will encourage the development of more new plants by partially guaranteeing investors' financial loss. Courtesy of Luminant hide caption

itoggle caption Courtesy of Luminant

The cranium of a creature who lived around 2 millions years ago, and was probably between the ages of 9 and 13 when it died. Scientists say this new species, Australopithecus sediba, may be a direct human ancestor. Brett Eloff/Courtesy of Lee Berger and the University of the Witwatersrand hide caption

itoggle caption Brett Eloff/Courtesy of Lee Berger and the University of the Witwatersrand

The fossil finger was found in a cave in the Altai Mountains of Siberia. Whoever that finger belonged to was neither human, like us, nor Neanderthal, the only other member of the human line known to be living in Europe at the time. Courtesy of Bence Viola hide caption

itoggle caption Courtesy of Bence Viola

Five fossilized human skulls show how the shape of the early human face evolved: (left to right) Australopithecus africanus, 2.5 million years old; Homo rudolfensis, 1.9 million years old; Homo erectus, 1 million years old; Homo heidelbergensis, 350,000 years old; Homo sapiens, 4,800 years old. Scientists believe that climate change had a major impact on the development of early humans. Chip Clark, Jim DiLoreto, & Don Hurlbert/Smithsonian Institution hide caption

itoggle caption Chip Clark, Jim DiLoreto, & Don Hurlbert/Smithsonian Institution

African elephants are expected to be at the center of a contentious debate about ivory sales at next week's CITES meeting. Delegates will try to resolve disputes about other animals, including bluefin tuna and hammerhead sharks. Dan Kitwood/Getty Images hide caption

itoggle caption Dan Kitwood/Getty Images

A life-sized reconstruction of the moment just before the dinosaur hatching and snake were preserved. The scales and patterning of the snake's skin is based on its modern relatives. The coloration of the hatchling is the artist's interpretation. Sculpture by Tyler Keillor/Photo by Ximena Erickson/Image modified by Bonnie Miljour hide caption

itoggle caption Sculpture by Tyler Keillor/Photo by Ximena Erickson/Image modified by Bonnie Miljour

When it comes to climate change, some look at the facts presented and see a coming catastrophe, others see a hoax. This difference in interpretation, social scientists say, has more to do with each individual's existing outlook than the facts. iStockphoto hide caption

itoggle caption iStockphoto

Redwoods, like those pictured above, receive up to 40 percent of their yearly water supply from fog — a resource that may be under threat, a new study suggests. iStockphoto.com hide caption

itoggle caption iStockphoto.com

The Intergovernmental Panel on Climate Change, regarded as the world's top climate science institution, reported that Himalayan glaciers could completely melt by 2035. Two numbers were transposed — it should have said 2350. Climate science naysayers cite the error as evidence of bias. Channi Anand/AP hide caption

itoggle caption Channi Anand/AP

An artist's Impression of "Inuk," a 4,000-year-old human whose remains were found in Greenland. Scientists have sequenced most of his DNA using tufts of his hair found in the 1980s. Nuka Godfredsen hide caption

itoggle caption Nuka Godfredsen

The migrant moth Autographa gamma (Silver Y), one of the species of migratory insects that have evolved sophisticated flight behaviors to optimize their migratory routes Ian Woiwod/Science hide caption

itoggle caption Ian Woiwod/Science

Storm clouds over Los Angeles. This year a strong El Nino has been responsible for severe weather over much of the U.S., including the heavy rains in California. David McNew/Getty Images hide caption

itoggle caption David McNew/Getty Images